Remove zlib

The library no longer uses zlib, so we can remove the option to build
with zlib.

CMakeLists.txt

@@ -5,8 +5,6 @@ else()
     project("mbed TLS" C)
 endif()
 
-option(ENABLE_ZLIB_SUPPORT "Build mbed TLS with zlib library." OFF)
-
 option(ENABLE_PROGRAMS "Build mbed TLS programs." ON)
 
 option(UNSAFE_BUILD "Allow unsafe builds. These builds ARE NOT SECURE." OFF)
@@ -169,14 +167,6 @@ endif()
 include_directories(include/)
 include_directories(library/)
 
-if(ENABLE_ZLIB_SUPPORT)
-    find_package(ZLIB)
-
-    if(ZLIB_FOUND)
-        include_directories(${ZLIB_INCLUDE_DIR})
-    endif(ZLIB_FOUND)
-endif(ENABLE_ZLIB_SUPPORT)
-
 add_subdirectory(library)
 add_subdirectory(include)